Equipment for operator served calls at an intermediate switching center





1. IN A TELEPHONE SWITCHING SYSTEM, TRUNK CIRCUITS, A FIRST AND A SECOND GROUP OF OTHER CIRCUITS, MEANS RESPONSIVE TO THE RECEIPT OF A CALL BY ONE OF SAID DRUNK CIRCUITS FOR INTERCONNECTING IT WITH ONE CIRCUITS IN EACH OF SAID GROUPS A DATA TRANSFER CIRCUIT, FURTHER MEANS RESPONSIVE TO THE RECEIPT OF SAID CALL FOR CAUSING SAID ONE TRUNK CIRCUIT TO EFFECT THE TRANSMISSION OF A SERVICE REQUEST SIGNAL TO SAID DATA TRANSFER CIRCUIT, AND MEANS RESPONSIVE TO 